1. Field of the Invention
The present invention relates to an electronic endoscope in which images of an object to be viewed are picked-up by a solid-state image pickup device in a field-sequential system.
2. Description of the Related Art
In general, in a known field-sequential type of electronic endoscope, an object is illuminated sequentially by separate illumination lights having three colors, i.e., red (R), green (G) and blue (B), so that images of the object are picked-up by a solid-state image pickup device. The color image signals thus obtained at different timings are digitized and temporarily stored in a memory for each color image signal, respectively. The color image signals stored in the respective memories are simultaneously read therefrom and converted into analog signals which are then output in accordance with need.
As can be understood from the foregoing, in the known electronic endoscope, it is necessary to provide three separate memories in which the three color image signals are temporarily stored in order to synchronize the three color image signals. However, this results in a need for complex circuitry, thus leading to an increase in the size and manufacturing cost of the endoscope.